Assessment and management of bronchitis

OVERVIEW ㅡ Bronchitis is an inflammation of the lining of the tracheobronchial tree. It is usually classified as acute or chronic. Acute bronchitis is characterized by cough occasionally associated with sputum production for less than 3 weeks. Chronic bronchitis is defined clinically as persistent productive cough for at least 3 months during a period of 2 consecutive years..

PATHOPHYSIOLOGY

Irritation of bronchial-lining tissue results in mucous membrane becoming hyperemic and edematous. Excess mucus production and bronchial smooth muscle hyperreactivity leading to bronchospasm. Increased airflow resistance leading to hypoventilation and hence hypercarbia and hypoxemia.

Table (1). Risk factors for bronchitis
TYPES	RISK FACTORS
Acute bronchitis	Smoking Respiratory irritants, for example, exposure to gases, air pollution Upper respiratory tract infections Chronic lung conditions, old age, decreased immunity increase the risk of developing acute bronchitis on exposure to respiratory irritants
Chronic bronchitis	Smoking Respiratory irritants, for example, exposure to gases, air pollution Frequent upper respiratory tract infections, allergies 50 years old Heritability has a moderate influence on the development of chronic bronchitis

ETIOLOGY

Table (2). Etiology of bronchitis
CAUSE	COMMENT
Acute bronchitis	Usually caused by viral organisms: influenza A and B viruses, parainfluenza virus, respiratory syncytial virus, coronavirus, adenovirus or rhinovirus Atypical bacteria are important causes in some cases Mycoplasma pneumoniae Chlamydia pneumoniae Bordetella pertussis
Chronic bronchitis	Smoking Environmental pollutants
Acute exacerbation of chronic bronchitis	Haemophilus influenza Moraxella catarrhalis Pseudomonas aeruginosa and Enterobacteriaceae more prevalent in patients with severe impairment of lung function Streptococcus pneumoniae Viral infections Chlamydophila pneumoniae Environmental factors (air pollutants, allergens, temperature changes, irritants like dust and cigarette smoke)
Commonly associated conditions	Upper respiratory tract infection Bronchial asthma Bronchitis associated with emphysema in chronic obstructive pulmonary disease

ASSESSMENT

Acute bronchitis usually begins as an upper respiratory infection with nonspecific complaints. Cough is the hallmark of acute bronchitis and occurs early. Frequently, the cough initially is nonproductive, but then progresses, yielding mucopurulent sputum. Fever, when present, rarely exceeds 39°C (102.2°F) and appears most commonly with adenovirus, influenza virus, and M. pneumoniae infections. The diagnosis typically is made on the basis of a characteristic history and physical examination, and should be differentiated from asthma or bronchiolitis as these latter diseases are usually associated with wheezing, shortness of breath, and hypoxemia.

          The hallmark of chronic bronchitis is a cough that may range from a mild to a severe and incessant coughing productive of purulent sputum. Coughing may be precipitated by multiple stimuli, including simple, normal conversation. Expectoration of the largest quantity of sputum usually occurs on arising in the morning, although many patients expectorate sputum throughout the day. The expectorated sputum usually is tenacious and can vary in color from white to yellow-green. Although sputum color of more green and yellow can be a predictor of potentially pathogenic bacteria, this is unreliable clinically.

DIAGNOSIS

LAB TESTS ㅡ CBC, pulse oximetry and arterial blood gas measurements, sputum cultures to rule out the presence of specific causative bacteria. The use of serum procalcitonin may guide which patients will need antibiotics. Spirometry may be performed several weeks after patient recovers to determine lung function and assess airway obstruction. Chest x-ray to rule out pneumonia.

MANAGEMENT

MEDICATIONS ㅡ First line for acute bronchitis; No treatment unless the presence of influenza virus, B. pertussis or M. pneumoniae or C. pneumoniae. FOR influenza virus, consider oseltamivir 75 mg orally BID × 5 days or zanamivir 2 puffs (5 mg/puff) BID × 5 days. FOR B. pertussis, azithromycin × 5 days at a dose of 500 mg on day 1 and 250 mg on days 2—5 can be prescribed or erythromycin 500 mg QID × 14 days or clarithromycin 500 mg BID × 7 days. FOR M. pneumoniae or C. pneumoniae, no therapy (no compelling data suggestive of improved outcomes as a result of treatment with antibiotic agents). Azithromycin × 5 days at a dose of 500 mg on day 1 and 250 mg on days 2—5 or doxycycline 100 mg BID × 5 days.

          FOR acute exacerbation of chronic bronchitis with acute bacterial infections, consider amoxicillin and clavulanate 500 mg orally q8hr × 5–10 days or trimethoprim–sulfamethoxazole 160 mg trimethoprim/800 mg sulfamethoxazole orally q12hr × 5–10 days or doxycycline 100 mg orally BID on day 1, then 100 mg orally per day × 5–10 days. Short-duration treatment with quinolones or macrolides (for 5 days) is not inferior when compared with longer duration treatment (7–10 days). EXAMPLES, levofloxacin 250 mg orally BID or 500 mg orally per day × 5 days or ciprofloxacin 250–500 mg orally BID × 5 days or clarithromycin 250–500 mg orally BID × 5 days or zithromycin × 5 days at a dose of 500 mg on day 1 and 250 mg on days 2–5. Second line for acute bronchitis (B. pertussis), trimethoprim–sulfamethoxazole 1600 mg per day × 14 days or 800 mg BID × 14 days.

ADDITIONAL TREATMENT ㅡ (1) Avoidance of environmental irritants. (2) Bronchodilators for the treatment of dyspnea. (3) Low-flow oxygen therapy during exacerbation. (4) Systemic steroids during exacerbation. (5) Antitussive agents (codeine and dextromethorphan) are effective for short-term symptomatic relief of cough in patients with acute and chronic bronchitis.

• 🌻 NOTE
  IN-PATIENT CONSIDERATIONS

  Initial Stabilization.
  Low-flow oxygen therapy and bronchodilators in emergency room for acute exacerbations.
  Initiation of appropriate antibiotics if required.
  Admission criteria include presence of high-risk comorbid conditions (pneumonia, cardiac arrhythmia, etc.), inadequate response to outpatient treatment and marked increase in dyspnea.

FOLLOW-UP

Re-evaluation of patient within 4 weeks for assessment of improvement of symptoms and need for oxygenation. Routine spirometry for patients with chronic bronchitis and inhaled corticosteroid therapy should be offered to stable patients with chronic bronchitis and FEV₁ <50% of predictive value with frequent exacerbations. Patient education include smoking cessation, avoidance of exposure to environmental irritants and restriction of heavy duties in patients with long-standing chronic bronchitis.

REFERENCES

• Wenzel, R.P. and Fowler, A.A. (2006). Acute Bronchitis. New England Journal of Medicine, 355(20), pp.2125–2130. Available at: https://pubmed.ncbi.nlm.nih.gov/17108344

  Albert, R.H. (2010). Diagnosis and Treatment of Acute Bronchitis. American Family Physician, [online] 82(11), pp.1345–1350. Available at: https://www.aafp.org/afp/2010/1201/p1345.html

  Blasi, F., Ewig, S., Torres, A. and Huchon, G. (2006). A review of guidelines for antibacterial use in acute exacerbations of chronic bronchitis. Pulmonary Pharmacology & Therapeutics, [online] 19(5), pp.361–369. Available at: https://www.sciencedirect.com/science/article/pii/S1094553905001112?via%3Dihub 

  ‌Falagas, M.E., Avgeri, S.G., Matthaiou, D.K., Dimopoulos, G. and Siempos, I.I. (2008). Short- versus long-duration antimicrobial treatment for exacerbations of chronic bronchitis: a meta-analysis. Journal of Antimicrobial Chemotherapy, [online] 62(3), pp.442–450. Available at: https://academic.oup.com/jac/article/62/3/442/731589